I am very happy to hear that you are working on the donation aspect, hopefully integrated into this forum and not (only) on the main website (propeciahelp.com), which nobody visits in any case. That is probably one of the most important aspects and improvements possible for this forum.
I understand that the minimalist idea doesnt vibe with the signature suggestion. Formatting text however (especially the standard text align stuff and coloring options) enables more readable posts. Coloring in red blue green and standard align options I think would be an improvement.